TODAY at the L'Enfant Plaza Hotel, sociologist James S. Coleman formally presents his report, "Public and Private Schools." In the draft version of that report, released last week, Mr. Coleman concluded that students in private schools achieve at a higher level than students in public schools and that private schools are safer than public schools because students are more disciplined. The report also found that private school students have more contact with their teachers and more opportunity to take part in school activities that develop personality and character traits. In his study, Mr. Coleman attempted to compare students in public and private schools from families of the same income level and equal educational backgrounds. But he qualified his findings with the caveat that there may be other factors he has not considered that account for the higher range of achievement by students in private schools.

Mr. Coleman's caveat is important. Private schools, which select their students not only on the basis of parental income or education but also on the basis of individual traits -- motivation, intelligence and so forth -- can hardly be fairly compared with public schools, which have to take all students.

It does not surprise us to learn from Mr. Coleman that private schools have more success with their select group of students than public schools do with whoever comes to the door. Nor is it surprising that private schools are able to have smaller classes that allow for more dealings among students and teachers. It is not even surprising to learn from Mr. Coleman that private schools can be more racially balanced than public schools. If a private school wants to be racially balanced, it can instruct its admissions director to deliver a racially balanced group of students.

So in a sense, Mr. Coleman's comparison of public and private schools amounts to a restatement of the obvious fact that private schools with more money and their own choices of students often get better results than public schools -- even though there are some private schools that do no better than some public schools -- and public schools can and do work in many areas of this country despite the current prevailing opinion to the contrary.

What we believe is this: Given commitment by parents and teachers, public schools can do as well as private schools at no extra cost to the family. And it will be too bad if Mr. Coleman's report becomes "evidence" for the argument against public schools, especially for the fight to gain approval of tuition tax credits. Tax credits for education will weaken public schools. They do not promise better education for American children. Mr. Coleman's report doesn't alter that central truth.